SOLUTION: A boy hikes 41 km and for the first part of the hikes he walks at 4km/h . For the rest of the hike he walks at 5km/h . If it takes him 9 hours to complete the hike calculate how fa

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Question 863669: A boy hikes 41 km and for the first part of the hikes he walks at 4km/h . For the rest of the hike he walks at 5km/h . If it takes him 9 hours to complete the hike calculate how far he walked each speed.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A boy hikes 41 km, and for the first part of the hikes he walks at 4km/h.
For the rest of the hike he walks at 5km/h .
If it takes him 9 hours to complete the hike calculate how far he walked each speed.
:
Let w = dist walked at 4 km/h
then
(41-w) = dist walked 5 km/hr
:
Write a time equation: time = dist/speed
w%2F4 + %28%2841-w%29%29%2F5 = 9 hrs
multiply by 20 to clear denominators
5w + 4(41-w) = 20(9)
5w + 164 - 4w = 180
5w - 4w = 180 - 164
w = 16 km at 4 km/hr
and
41 - 16 = 25 km at 5 km/hr
:
:
Check this; find the time at each speed.
16/4 = 4 hrs
25/5 = 5 hrs
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total: 9 hrs